Air flow regulating device
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Solution Overview
Problem
Conventional hair dryers with single-phase series motors have a short lifespan due to brush wear, which leads to carbon powder contamination and inefficiencies, and existing solutions do not adequately address these issues.
Innovation Solution
A hair dryer with a single-phase permanent magnet brushless motor and a simple drive control circuit, featuring a stator and rotor with magnetic poles not exceeding six, and a drive control circuit that includes a position detector and motor driver to manage the motor's operation, reducing wear and improving longevity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single-phase series motor with brush and commutator is used, then the motor can drive the impeller, but the brush wears away resulting in short lifetime and carbon powder contamination
Solution Approach 1:
The patent replaces the mechanical brush-commutator system with a brushless motor design. The single-phase series motor is transformed into a brushless motor by removing the commutator and brushes, and introducing a rotor winding system that generates rotating magnetic field without mechanical contact. This substitution eliminates carbon powder contamination and extends product lifetime.
Solution Approach 2:
The patent changes the fundamental operating parameters of the motor by transitioning from a brushed DC motor system to a brushless AC motor system. The motor now operates on AC power directly, with the rotor winding configured to create a rotating magnetic field that interacts with the stator field, eliminating the need for mechanical commutation.
2Object-generated harmful factors
If a brushless motor is used, then carbon powder contamination is reduced, but the motor structure becomes more complex
Solution Approach 1:
The patent makes the motor universally compatible with standard AC power supplies (50Hz or 60Hz mains power), eliminating the need for separate DC power conversion systems. The motor structure integrates multiple functions: the stator winding serves as both the excitation winding and the main power winding, while the rotor winding simultaneously provides both field generation and commutation functions through its specific connection configuration.
3Loss of energy
If the stator and rotor have more magnetic poles, then the motor efficiency is improved, but the manufacturing complexity and cost increase
Solution Approach 1:
The patent adopts a practical approach by using a moderate number of magnetic poles (2-4 poles) rather than maximizing the pole count. This partial action provides sufficient motor efficiency for hair dryer applications while keeping the manufacturing process simple and cost-effective. The design recognizes that beyond a certain point, increasing pole count yields diminishing returns relative to the increased manufacturing complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution extends the product lifetime, reduces costs, and minimizes carbon powder contamination by using a brushless motor with efficient drive control, enhancing operational reliability and user safety.
Implementation Method 1
The single-phase permanent magnet brushless motor comprises a stator and a rotor which can rotate relative to the stator. The stator surrounds the rotor and comprises a stator core and a single-phase winding wound around the stator core. The rotor comprises a shaft and a permanent magnet fixed to the shaft.
Implementation Method 2
the circuit board is provided with a power supply terminal and an inverter configured to provide an alternating current for the single-phase winding
Implementation Method 3
a position detector and motor driver is electrically connected between the power supply terminal and the inverter, which is configured to detect a magnetic field position of a rotor of the single-phase permanent magnet brushless motor and output at least two trigger signals which are basically inverted with respect to each other for the inverter
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
An air flow regulating device (100) includes a housing (110), an air supply unit (130) and a circuit board (140) which are arranged inside the housing (110). The air supply unit (130) includes an impeller (131) and a single-phase permanent magnet brushless motor (10) configured to drive the impeller (131). The single-phase permanent magnet brushless motor (10) includes a stator (101) and a rotor (60, 102) which can rotate relative to the stator (101). The stator (101) includes a stator core (212) and a single-phase winding (1011) wound around the stator core (212). The rotor (60, 102) includes a shaft (551) and a permanent magnet (66) fixed to the shaft (551). Numbers of magnetic poles of the stator (101) and the rotor (60, 102) are the same and not greater than six. An outer diameter of the stator core (212) is less than 35mm and/or an axial thickness of the stator core (212) is between 10mm and 20mm.